Bottle closure



March 14, 1933. H, W H 1,900,963

BOTTLE CLOSURE I Fil ed March 27, 1950 iATroRNE Patented Mar. 14, 1933 UNITED, STATES PATENT OFFICE ALBIN H. WABTH, O1 BALTIMORE, MARYLAND, ASSIGNOR TO CROWN CORK & SEAL GOM- PANY, 1110., O! NEW YORK, 11'. Y., A. CORPORATION OF NEW YORK BOTTLE CLOSURE Application filed March 27, 1980. Serial No. 439,295.

My invention relates to bottle closures, and more particularly to bottle closures of the type in which an annular sealing gasket is formed in the metallic shell adjacent the skirt thereof.

Heretofore, I have devised a bottle closure of the type above referred to, in which the sealing gasket is composed of plastic material. including latex and a mineral filler, such as bentonite.

Ca s embodying the above characteristic have een found suitable for use in the packaging of various foodstufis and beverages, but have been found unsuited for use where fairly high pressures develop within a container, or

where, after packaging and sealing, the container is subjected to high temperatures for the purposes of pasteurization, sterilization or further treatment of the contents of the container, such as the cooking of the contents thereof. This is due to the fact that while the lastic material of the gasket, when applie to a container by the ordinary cappin machinery, will readily conform to the nec of the container so as to form a liquid and.

gas tight joint, this material, even after once setting within the cap, will soften when subjected to high temperatures and flow sufliciently to cause the loss of the liquid and gas tight seal, not only permitting the escape of the liquid or gaseous contents of the container, developing what is known as a leaker, but permitting air to subsequently enter the container. and cause deterioration of the contents thereof.

With the above conditions in mind, I have produced a bottle closure of the general type above referred to, wherein the character of the packing gasket is such as to permit the production of. the caps by the methods usually employed in the manufacture of caps of the general type to which the invention relates, and yet, when subjected to heat of an elevated temperature, will take a permanent set instead of softening and flowing in the manner above described.

Such a closure ossesses all of the advantages of closures including packing gaskets formed of plastic composition consisting of latex and a mineral filler, so far as production of a cap and its application to a container 1s concerned. and will, in addition thereto, possess all of the desirable characteristics of a vulcanized rubber gasket-lined closure, and

be without the undesirable characteristics of either.

In a closure embodying the invention, not only will-the gasket take a permanent set when subjected to an elevated temperature, but in so doing will increase the effectiveness of its seal in preventing the escape of gases from the container. In actual practice, I have determined that while with the use of a plastic gasket, the maximum pressure which the closure will resist does not exceed 80 pounds, with the closure of my present inventlon, the gasket will withstand a pressure of 140 pounds, or more.

It is a recognized fact that soft vulcanized rubber possesses characteristics which, when brou ht in contact with various substances, will unpart to such substances the characteristic taste of the rubber compound. Such provided with a channel adjacent said skirt, and a gasket within said channel, consisting of a rubber compound having a low content of a vulcanizing agent, whereby upon the subjection of a container, with a cap applied thereto, to heat, said gasket will be semivulcanized; and in such other novel characteristics as are hereinafter set forth and described, and more particularly pointed out 'in the claims hereto appended.

Referring to the drawing,

Fig. 1 isa bottom plan view of a bottle cap embodying the invention; and

Fig. 2 is a cross section thereof.

embodying my invention. I employ an or inary metal shell with its 5 sklrt, by means of which it may be attached to the bottle. The top of the shell, adjacent saild skirt, is provided with an annular channe In the drawing, the top of the shell is indicated at a, the skirt thereof at b and the annular channel at c. In the type of cap illustrated, a fluted skirt, characteristic of what is known as crown caps, is disclosed and the scale of the drawing is much enlarged. Such caps are used with ordinary bottles and with various other types of containers, and the construction of the shell may e varied according to the type of container with which it is to be used.

Seated within the channel 0 is a packing gasket d consisting of a rubber compound,

referably formed of a water dispersed rub er, a mineral filler, a" vulcanizing agent, a

25 miscible accelerator belonging to a class of organic compounds known as piperidine compounds and a volatile alkali. The filler preferably used is bentonite.

The rubber constituent in the compound is approximately 25%; the bentonite, approximately 45%; the vulcanizing agent, sulfur, about .2 of 1%; zinc stearate, about .2 of 1% and free ammonia about .1 of 1%. The rubr constituent and the bentonite are at first thoroughly mixed. To this is added the sulfur, zinc stearate and free ammonia in suspension in water at a temperature of approximately 120 F. The accelerator is then added in solution form, the water of solution being at approximately 120 F.

It will be noted that the sulfur content is very low so that at the most, if subjected to heat at the proper vulcanizing temperature, there will only be a semi-vulcanization of the compound. This .is highly desirable since the gasket, when the cap is in place on a container and is subjected to heat, will take a permanent set which will preclude its extrusion from between the metal shell and the neck of the container as a result of pressures developed within the container, but will develop none of those flavors characteristic of soft vulcanized rubber.

The gasket may be formed in the channel by an ordinary pouring operation, the channel being of sufficient depth to provide sufficient body or thickness to the gasket to permit the effective compaction thereof under the high pressures used in applying such caps to the containers. 1

The ammonia is used merely to facilitate the placing of the accelerator in solution and its incorporation in the plastic mass. I

The compound is such'that it cannot be 5 produced by the ordinary rubber milling opcarbonated beverages,

.application of heat to the erations, and the accelerator used must be ca able of going into solution.

n the completed cap there will undoubtedly be no trace of ammonia in the gasket, and the presence of the vulcanizing agent and the accelerator is indicated solely by the properties inherent to the gasket. .Consequently, compounds other than that herein disclosed, may impart to the gasket the desired characteristics.

Since the gasket, after application to the channel of the shell, may be allowed to set under normal temperatures or under gentle heat, when the cap is applied to a container, the material of the gasket will be semi-plastic so as to readily conform to any irregularities in the neck of the container with which the gasket contacts. By locating the gasket in a channel it will not spread ,to any material extent when subjected to pressure, although it will readily be formed to the neck of the bottle by reason of its plasticity.

It is obvious that if the cap is used upon containers which are not, after the application of the cap, subjected to high temperatures, a seal will be obtained which is eflective at the ordinary pressures present with which do not require sterilization, said pressures usually not exceeding pounds per will also be effective withcontainers filled with foodstufis of various kinds which are not subjected to temperatures for cooking or sterilization following the application of the ca it has been found, however, that the seal square inch. The seal" ceases to be effective where the pressures de- Veloped exceed 80 pounds, or Where the container, With the cap applied, is subjected to elevated temperatures, since the high pressures, alone or in the presence of high temperatures, will force the semi-plastic mass from betweenthe channel and the neck of v the container so as to break the seal, and the high temperatures will increase this tendency and also cause the plastic compound to flow within the contents of the container. I am referring'to the conditions present when the compound contains no vulcanizing agent and no accelerator.

In the cap of the invention, however, the container, with the cap applied, will activate the vulcanizing medium used and thus, by reason of the contact of the compound with the metal shell, cause a rapid semi-vulcanization of the compound of which the gasket is formed before the pressures developed are sufficiently high to cause the extrusion of the compound in the manner above referred to. Furthermore, the application of heat at an elevated temperature, instead of softening the mass, will give it a permanent set. During the application of heat there will also be a tendency of the compound to expand and this will reano e-ea cap and yet be et iecti entina iron oi lealrers or the it is essential that the content of rulagent, sulfur, very materially 3 below lowest content heretofore used in vulcanising rubber, A higher content oi ruicanising medium will prevent the gas ket having imparted thereto the desired. degree oi rigidity or permanency of set with the conditions of use presentwith such caps, and will impart thereto a distinct rubber flavor which will be imparted to the contents of the container.

it is not my intention to limit the invention to a gasket consisting of the precise proportions or ingredients herein. specified, such being; stated merely as disclosing the most effective compound of which l are. aware. The low content of the Vulcanizing medium, and the presence of an accelerator, however, are essentials in order to secure a cap having the desired characteristics.

Having described the invention, what I claim as new and desire to have protected 9 by Letters Patent, is

l. A bottle cap embodying therein a metal shell and a skirt therefor, the top of said shell being provided with a channel adjacent said skirt, and a gasket within said channel, consisting of a rubber compound having a low content of a vulcanizing agent, whereby upon the subjection of a container, with a cap applied thereto, to heat, said gasket will be semi-vulcanized.

ll 2. A bottle cap embodying therein a metal shell and a skirt therefor, the top bit said shell being provided witha channel adjacent said skirt, and a gasket Within said channel, consisting of a rubber compound embodying therein water dispersed rubber, a mineral filler, a low contentof a vulcanizing agent, and an accelerator, whereby upon the sub jcction of a container, with a cap applied thereto, to heat, said gasket will be semivulcanized.

3. A bottle cap embodying therein a metal shell and a skirt therefor, the top shell being provided with-a channel adjacent said skirt, and a gasket within said channel, consisting of a rubber compound embodying of said therein water dispersed imbbe", mineral filler, a low content at a rulcaniarngagent,

and a miscible accelerator, whereby upon. subglection' ot a containenwith a cap thereto, to heat, will be vulcanized, v

a 4;, A. bottle cap embodying rein. metal shell. and shirt theretor, top of said shell being with a channel adja cent said sl a gasket within said rubber compound semi channel, con U embodying therein dispe sed. rubber, a fil ies, a content at l sultur, and an accele or, wh subject on of a con. thereto, to heat, so semi vulcan-iaedi Abottle cap embodying thereina shell and a fluted slrirt therefor, the top oi. said shell being provided with a channel adjacent said skirt, and a gasket within channel, consisting of a rubber compound. embodying therein water dispersed rubber, a mineral tiller, a low content of a vulcanizing agent, and an accelerator, whereby upon the subjection of a container, with a cap applied thereto, to heat, said gasket will be semi-vulcanized.

6. A bottle cap embodying therein a metal shell and a fluted skirt therei -or, the top of said shell being provided with a channel adgaslret will i. l llll jacent said shirt, and a gasket within said .hhldllhl llil. WARTH,

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Mill 

